Vascular endothelial growth factor as a survival factor in tumor-associated angiogenesis.

This review focuses on vascular endothelial growth factors (VEGF), a group of structurally-related proteins that serve as key growth factors for tumor-associated angiogenesis. Pathways induced by VEGF proteins that regulate biological functions of key cell types involved in tumor angiogenesis, including vascular endothelial cells, pericytes and tumor cells, are discussed. Strategies that are currently being developed and tested based on the emerging definitions of the roles of the multiple cell types involved in tumor vessel development, their selective production of VEGF-related proteins and other pro-angiogenic growth factors, their expression of associated receptors as well as identification of signal transduction pathways involved in VEGF-induced tumor survival and tumor-associated angiogenesis will be reviewed.